Variable air volume (VAV) systems are widely accepted as energy efficient means of obtaining zone control of temperature. A variable air volume system supplies a constant temperature of air (55.degree.) while adjusting the position of a damper in the air supply duct to vary the volume of air supplies to the space. The volume of air changes to compensate for changing loads in the zone to maintain a constant temperature. A properly designed VAV system can reduce operating costs by as much as 50%. The great majority of VAV controllers are based on a pneumatic system which uses a large air compressor and associated tubing in the control, i.e., the thermostats and the positioning arrangements. Electronic controls appear attractive for smaller installations, retrofit situations and where optional features are desired. Furthermore, with the ever decreasing cost of electronic components, logic chips and elements, it is likely electronic controls will become increasingly attractive.